The lattice thermal expansion of zirconium-based samples containing tin, niobium, and iron elements at a temperature range of 30–870°C with intervals of 40°C was studied by in situ hightemperature X-ray diffraction (HT-XRD). The a- and c-axes lattice constants of the hexagonal Zr crystal structure for the zirconium-based samples were calculated by Pawley refinement using the in situ HT-XRD spectra. The a-axis lattice parameters for the zirconium-based samples with tin element overall decreased, whereas those for the samples containing niobium or iron elements are not declined, as compared to those for a pure zirconium sample. It suggests that the lattice thermal expansion along the a-axis direction of the hexagonal Zr crystal structure for zirconium-based samples was suppressed by the tin element. This effect is the greatest when the content of tin element added in zirconiumbased sample is 3wt%. On the other hand, the c-axis lattice parameters for all the zirconium-based samples overall increase as compared to the pure zirconium, indicating no suppression effect by tin, niobium, and iron elements, in contrast to the a-axis lattice constants.

• Jeong Min Ha(Yeungnam University, 280, Daehak-ro, Gyeongsan-si, Gyeongsangbuk-do)
• Sang Ho Lim(Korea Atomic Energy Research Institute, 111, Daedeok-daero 989beon-gil, Yuseong-gu, Daejeon)
• Young-Sang Youn(Yeungnam University, 280, Daehak-ro, Gyeongsan-si, Gyeongsangbuk-do) Corresponding author